OFFSET
1,3
REFERENCES
J. Peters and J. Stein, Mathematische Tafeln. Revised Russian Edition, 1968, Moscow.
FORMULA
a(n) = floor(log_10(A000182(n))) + 1. - Franklin T. Adams-Watters, Mar 29 2014
EXAMPLE
a(7) = 8 since the 7th tangential number is 22368256, which has 8 decimal digits.
PROG
(Python)
from sympy import bernoulli
def A047894(n): return len(str(abs(((2-(2<<(m:=n<<1)))*bernoulli(m)<<m-2)//n))) # Chai Wah Wu, Apr 14 2023
CROSSREFS
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
a(1) corrected by Chai Wah Wu, Apr 14 2023
STATUS
approved